Arbitrum bug causes brief delay in network operation; now fixed

A bug in Arbitrum's sequencer code caused a brief pause in the network's ability to batch transactions to the Ethereum blockchain.

As a Layer 2 network, Arbitrum batches up transactions and submits them in a single transaction to Ethereum in an effort to help reduce the load on the main blockchain. To do so, it uses what's called a sequencer to gather these transactions, order them and batch them onto Ethereum.

Yet a bug in the sequencer's code stopped it from being able to batch transactions onto Ethereum, according to Arbitrum developers. This caused a brief outage where transactions were not getting confirmed on the main chain.

"When the Sequencer tried to post a batch on-chain, the bug hit and the transaction reverted," the official Arbitrum developers Twitter account said on Wednesday.

There was a bit of confusion when this happened over the levels of ether in the sequencer's wallet. When the system is working as designed, the wallet gets refunded with the amount of transaction fees that it spends. Since the transactions were not getting confirmed on Ethereum, a second wallet — that is set up to automatically refund it — didn't do so. This worked as intended and didn't cause the outage.

After the bug was fixed, the second wallet continued to refund the sequencer's wallet, and it carried out its duties as normal.